Paper-handling apparatus



Oct. 22, 1968 G. o. DEL VECCHIO ETAL 3,406,950

PAPER-HANDLING APPARATUS Filed Oct. 11, 1966 5 Sheets-Sheet l INVENTOR. GEORGE D. DEL VECCHIO JOHN A. HALLAGAN BY Oct. 22, 1968 e. o. DEL vsccr-uo ETAL 3,

PAPER-HANDLING APPARATUS Filed Oct. 11, 1966 5 Sheets-Sheet 2 INVENTOR GEORGE D. DEL VEGCHIO J H By 0 N A HALLAGAN ATTORNEYS Oct. 22, 1968 Filed Oct. ll, 1966 G. D. DEL VE CCHIO ETAL PAPER HANDLENG APPARATUS 5 Sheets-Sheet 3 FIG. 3

INVENTOR. GEORGE D. DEL VECCH IO BY JOHN A. HALLAGAN a QC? @ZEYS Oct. 22, 1968 G. D. DEL VECCHIO ETAL 3,

PAPER-HANDLING APPARATUS Filed Oct. 11, 1966 5 Sheets-Sheet 4 INVENTOR. GEORGE D. DEL VECCHIO BY JOHN A. HALLAGAN TORNEYS Oct. 22, 1968 5. D. DEL VECCHIO ETAL 3,406,960

PAPER -HANDLING APPARATUS 5 SheetsSheet 5 Filed Oct. ll, 1966 2 mm mm INVENTOR. GEORGE D. DEL VECCHIO JOHN A. HALLAGAN United States Patent Olfice 3,406,960 Patented Oct. 22, 1968 3,406,960 PAPER-HANDLING APPARATUS George D. Del Vecchio, Briscoe Cove, North Rose, and John A. Hallagan, Pittsford, N.Y., assignors to Xerox Corporation, Rochester, N.Y., a corporation of New York Filed Oct. 11, 1966, Ser. No. 585,784 3 Claims. 01. 271 s ABSTRACT OF THE DISCLOSURE This invention relates to paper handling apparatus and, in particular, to a paper handling apparatus adapted to pre-condition sheets of paper for forwarding to a xerographic processing station.

More specifically, this invention relates to a paper handling mechanism adapted to seriatim feed paper sheet material and to pre-condition the paper sheet material for fusing in a xerographic fixing apparatus.

In the xerographic process, a plate comprising a layer of photoconductive material on a conductive backing is given a substantially uniform electric charge over its surface and then exposed to the subject matter to be reproduced by various projection techniques. This exposure discharges the plate in accordance with the light intensity reaching it, thereby,"creating an electrostatic latent image on or in the plate.

Development of the image is effected by developers which comprise, in general, a mixture of suitable resin based powder, hereinafter referred to as toner, and a car'- rier material which functions to carry and to generate triboelectric charges on the toner. More specifically, the function of the carrier material is to provide mechanical control of the toner, or to carry the toner to an image surface, and simultaneously provide almost complete homogeneity of charge polarity. In the development of the image, toner powder is brought into surface contact with the photoconductive layer and is held thereon electrostatically in a pattern corresponding to the electrostatic latent image. Thereafter, the developed xerographic image may be transferred to a support material to which it may be fixed by any suitable means.

As the science of xerography has progressed, faster automatic xerographic reproducing machines have been developed necessitating improved fixing apparatus capable of fixing the xerographic toner powder image to the support material at a rate compatible with the higher speed machines. In fixing the toner powder to the support material it is desired to obtain the highest possible quality of reproduction from the original document and in many applications desirable to obtain a reproduction having a better quality than the original document. Such a fixing apparatus is disclosed in copending application Ser. No. 585,971 filed concurrently herewith on Oct. 11, 1966, in the names of Gilbert A. Aser et al. and for convenience of illustration the invention of this application will be described with reference to its use in an automatic xerographic reproducing machine utilizing such a fixing apparatus, although it is not to be limited thereto.

In the fixing apparatus disclosed in the above reference copending application, it is necessary that a sheet of support material passing through the fixing apparatus be closely regulated as to moisture content. In such a fixing apparatus, a sheet of support material is electrostatically secured to a transport mechanism for pre-heating prior to selectively fixing the toner powder images onto the support material sheet.

Selective fusing, that is, permanently fixing a desired toner powder image to the support material without fixing unwanted background toner powder images, is enhanced by pro-heating the support material to a specified temperature prior to its being brought into thermal contact with a source of intense radiant energy. In order to preheat the paper support material to the desired temperature prior to exposure to the intense radiant energy, it is necessary that the paper sheet material be delivered to the preheat roller suitably conditioned as to moisture content to be electrostatically secured thereto. If the support material is not properly conditioned to control the moisture content, the electrostatic bond between the support material and the pre-heat roller will be weakened due to the moisture combining with impurities in the atmosphere to become electrolytic, thereby, conducting the static electric charges between the support material and the pre-heat roller allowing the support material to become loosened therefrom. High moisture content in the support material provides a transfer media for the electrostatic charges between the support material and the pro-heat roller which weakens the electrostatic bond between the two'bodies allowing the support material to become easily separated from the pre-heat roller.

Since it is desired in automatic xerographic reproducing machines to retain a large quantity of sheet material in the machine for xerographic processing, it is necessary that this quantity of sheet material be pre-conditioned as to moisture content and be maintained at the proper conditioning prior to fixing in the fusing apparatus for the above reasons. In the event that the paper sheet material is improperly conditioned prior to entering into the xerographic fixing apparatus, the heat from the preheat roller will be utilized to decrease the moisture content of the sheet material. Upon exposure of the support material to the intense radiant energy, this energy will be utilized to drive the moisture out from the sheet material rather than fusing the xerographic toner powder to the sheets, and the distillants from the sheet material will condense on the fixing apparatus at the radiant energy position eventually rendering the apparatus inoperable for its intended purposes.

The controlling of the moisture content of paper sheet material is also a critical factor in reliable paper feeding. Various types of deformities occur to distort a stack of sheet material, especially the topmost sheet, during conditions of high relative humidity. There are several types of distortions that can occur resulting in 'misfeeding or curling the topmost sheet as it is forwarded creating paper jams. Since it is desirable for high speed xerographic reproducing machines to be operable throughout extreme ambient environmental conditions, and to be operated by unskilled, casual operator throughout such conditions, a major problem existed in feeding sheet material during environmental extremes and conditioning the sheet material so that it may be selectively fused by a xerographic fixing apparatus.

It is, therefore, an object of this invention to improve paper handling apparatus for automatically advancing sheet material during conditions of extreme relatively humidity.

Another object of this invention is to condition sheet material for forwarding to a xerographic fixing apparatus.

handling mechanism by controlling the moisture content of the sheet material while in the sheet handling apparatus.

These and other objects are attained in accordance with the present invention wherein is provided a pack advancer mechanism adapted to seriatim feed paper sheet material pre-conditioned as to moisture content by means of heaters controlled through the operation of appropriate sensing devices.

Further objects of this invention, together with additional features contributing thereto and advantages accruing therefrom, will be apparent from the following description of an embodiment of the invention when read in conjunction with accompanying drawing, wherein:

FIG. 1 illustrates schematically a preferred embodiment of a xerographic reproducing machine having a sheet handling mechanism constructed in accordance with the invention;

FIG. 2 is an enlarged front view of the paper handling apparatus with portions broken away to show the internal mechanism of the apparatus;

FIG. 3 is a top view of the paper handling apparatus shown in FIG. 2;

FIG. 4 is a sectional view of the paper handling apparatus shown in FIG. 3 taken along lines 44 of FIG. 3; and

FIG. 5 is a side elevation view of the paper handling apparatus shown in FIG. 2 with parts broken away to better show the internal construction thereof.

Referring now to the drawings, there is shown in FIG. 1 an automatic Xerographic reproducing machine having an apparatus for fixing xerographic toner powder images on support material constructed in accordance with heretofore mentioned copending application Ser. No. 585,971 filed concurrently herewith on Oct. 11, 1966, in the names of Gilbert A. Aser et al.

Unfused sheet support material bearing xerographic toner powder image is electrostatically secured to the heated roller to be directly heated at a constant controllable rate by means of the heat conducted from the roller 20 to the sheet support material. As the support material is advanced by means of the roller 20, the tonerpowder-image-bearing support material is brought into thermal contact with a source of intense radiant energy 42 whereat the xerographic toner powder image is selectively fixed to the support material.

After selectively fixing the toner powder image to the surface of the support material, the support material is removed from the roll by means of a pick-otf arm pivotally mounted adjacent to the roller 20 and engaging a slot provided therein. The pivot arm is tapered to a point and positioned so that the point rides below the surface of the roller 20 enabling it to engage the underside of the support material thereby stripping the sheet from the roller. As the support material is stripped from the roller 20, it engages suitable guides for forwarding to the vac uum sheet transport 52 to be further processed and transported out of the xerographic reproducing machine.

Referring to the drawings which illustrate a preferred embodiment of the invention, there is shown a paper handling apparatus including a front frame plate 301 and rear frame plate 302 connected together and maintained in spaced relation to each other by cross members 303 and tie rods 304.-A stack or pile of sheets, indicated as 305, is supported on a movable table or tray 41 between the frame plates 301 and 302. The tray 41 is shaped in a concave configuration for supporting the stack of sheets and has depending side 306 extending downward to which are secured a pair of extension arms 307 carrying a pair of rollers 308. The rollers 308 are adapted to ride in guide channels 309 secured to frame plates and 302. Thus, the tray '41 is movable in vertical direction between the two frame plates 301 and 302, and is guided in its vertical movement by the rollers308 in the guide channels 309.

To environmentally condition the stack of paper support material positioned on tray 41, the pack advancer and sheet feeding mechanisms are enclosed in chamber comprising the frame plates 301, and 302, the frame plate 301 forming an enclosure over the top of the paper handling apparatus. A door 612 is suitably secured as by hinges to frame plate 302 to form a seal between the door 612 and the frame plates bymeans of insulating material. A heater element H-2 is supported beneath the tray 41 by means of support bracket 602 suitably positioned between frame plates by means of angle brackets 604. The heater elements H-1 and H-2 are preferably of a type such as Electromesh strip heaters having an electrical rating of two watts/sq. in. available from Electrofilm Inc., Cherry Hill, NJ. The upper heating element H-l is supported by support bracket 601 suspended from the cover 301 by means of angle brackets 603 appro--- priately secured thereto.

The tray 41 is supported from a pair of cables 310 by means of brackets 311 secured to tray side 306. Each of the cables 310 has one end secured to the brackets 311 by means of connectors 312, and the other end secured to the pulley 313. The pulleys 313 are fixed to a shaft 320 on opposite sides of the tray between plates 301 and 302. Shaft 320, journaled in suitable bearings mounted in the plates 301 and 302, is driven to raise or lower the table by means of a gear 321 mounted on a portion of the shaft 320 which extends through the frame plate 302. Driving power is supplied to a gear to rotate shaft 320 to raise and lower table 41 by a worm gear on the drive shaft of an index motor MOT-1. For further information concerning the pack advancer reference is bad to copending application Ser. No. 557,063, filed June 13, 1966, in the names of V. C. Draugelis et al.

To control moisture content of the sheet material 305 supported on the tray 41, a humidity sensor HU-l, preferably a humidity controller such as model H46A available from the Minneapolis-Honeywell Regulator Company,'Minneapo1is, Minn., is secured to frame plate 301 to sense the relative humidity of the chamber 10, and-is electrically connected in a circuit including the heater elements H-1, H-2, and thermostat TH-l preferably a them'ostat such as Type A snap-acting fixed temperature thermostat available from Stevens Manufacturing Company Inc., Mansfield, Ohio, the thermostat being supported from the cover plate 301 by means of a bracket 607 appropriately secured thereto.

In operation the heating elements H-1 and I-I-2 are energized by the humidistat HU-l to control the relative humidity within the environmental chamber or housing 10. When the moisture content of the atmosphere within the chamber 10 rises above a desired level, the heating elements H-1 and H2 are energized to raise the temperature to a point where a psychometric spread between the dry bulb and wet bulb temperatures of the atmosphere produces a relative humidity within the desired limits or, the temperature is raised to a point whereat the percentage of moisture content in the air relative to the maximum moisture content the air could hold at the temperature is no more than 40%. However, to prevent the temperature in the chamber from exceeding a desired amount, the thermostat TH-l is connected into the electrical circuit to open the circuit, de-energizing the heaters, whenever the temperature within the chamber exceeds a predetermined amount, preferably at F.

The preconditioned paper sheet support material is forwarded from the top of the stack 305 for transportation to the selective fuser 42 by means of a suitable sheet feeding mechanism comprising vacuum feet 365 secured at one end to a hollow manifold tube 366 journaled at opposite ends at pivot arms 367. One end of the tube 366 is sealed and has a suitable adjustable limiting valve 316 to control the suction pressure, and the opposite end of the tube is connected by a flexible conduit 368 to the inlet of a vacuum pump, not shown, driven by suitable motor. A cam follower arm 369, carrying cam follower 370 is also secured to the manifold tube 366. The opposite ends of the pivot arm 367 are secured to the rock shaft 371 journaled in plates 301 and 302. For more details concerning the specific construction of the vacuum sheet feeder shown, reference is made to J. W. Wagner, US. Patent No. 3,241,830.

To ensure the separation of single sheets from the stack of sheet material by the vacuum sheet feeder, the pressure side of the vacuum pump is connected by conduits 397 to manifold conduits 395 positioned near the leading edge and leading corners of the stack of sheet material 305. Apertures 396, in the manifold conduits direct air under pressure toward the leading edges of the topmost sheets of the stack whereby these sheets are loosened from each other and lifted to the proper height for removal by the suction feet. When the suction feet are in contact with the sheet, air is drawn into the pump through adjustable valve 316.

To maintain the relative humidity conditions within the chamber 10, the air discharged through the apertures 396 toward the leading edges and corners of the topmost sheets of the stack is heated to lower the relative humidity of the chamber atmosphere. The manifold conduits 395 are connected by means of conduits 397 to a manifold 608 having a thermostat TH-2 secured therein to sense the temperature of the air passing from the manifold through the conduits into the manifold conduits 395 for discharge into the sack of paper sheet material. The thermostat TH-2 is connected into an electrical circuit including a heater 609, for heating the air discharged through the manifold conduits 395, and is set to deactuate the heater whenever a predetermined temperature 5 is exceeded, preferably at 110 F. Heater 609 is appropriately secured to front frame plate 303 and is preferably a 300 watt 115 volts Hotwatt thermostatically controlled heater manufactured by Hotwatt Inc., Danvers, Mass.

In operation, as the relative humidity within the chamber 10 increases above 40%, the heating elements H1 and H-2 are actuated by means of the humidistat HU-l. The temperature within the chamber 10 is then increased to lower the relative humidity within the chamber until such time as the relative humidity falls below 40% thereby de-actuating the humidistat HU-l, or the temperature within the chamber increases above 110 F., thereby actuating the thermostat TH-l to interrupt the electrical power circuit to the heating elements H-1 and H-2. The operation of the heater 609 is controlled independently of the humidistat HU-l by means of the thermostat TH-Z to maintain the air within the manifold 608 at approximately 110 F., the thermostat TH-2 interrupting the power to the heater 609 in the event the manifold air temperature exceeds the thermostat setting.

While there has been shown and described one embodiment of this invention, it is obvious that changes in form could be made without departing from the invention; and it is intended, therefore, that the invention be not limited to the exact form shown and described nor to anything less than the whole of the invention as set forth in the appended claims.

What is claimed is:

1. An apparatus for conditioning and seriatim feeding sheets of support material through a path of movement to a xerographic fixing apparatus including means defining a chamber having an opening adapted for the passage of sheets of support material therethrough,

retaining means for supporting a stack of sheet support material within said chamber, feeding means positioned within said chamber adapted to forward the topmost sheet of said stack of sheet support material through said chamber opening,

first heating means positioned within said chamber adapted to regulate the environmental atmosphere within said chamber,

first sensing means operatively connected with said first heating means to actuate said first heating means in response to a predetermined relative humidity within said chamber,

aerating means positioned in cooperative relation to the stack of sheet material supported by said retaining means to introduce a controlled discharge of aeriform fiuid against the leading edge and leading corners of said stack creating an air cushion so that a plurality of the topmost sheets will be fanned and separated from said stack,

second heating means within said aerating means to preheat air discharged against the sheets of the stack for the preconditioning thereof, and

second sensing means operatively connected with said second heating means to inactivate said second heating means in response to a higher than predetermined temperature within said aerating means.

2. The apparatus of claim 1 wherein said first sensing means includes a humidity sensor adapted to control the relative humidity within said chamber to a predetermined percentage.

3. The apparatus of claim 2 wherein said first sensing means also includes a temperature sensor adapted to deactuate said heating means in response to a predetermined maximum temperature.

References Cited UNITED STATES PATENTS 1,459,391 6/1923 Clausen 236-44 2,037,695 4/ 1936 Brownlee 34-48 3,180,038 4/1965 Chafee 3448 X EDWARD A. SROKA, Primary Examiner. 

